Table A1.
Results of the Principal Component Analysis over the data of four variables relating to general cognitive ability.
| Principal Component Analysis | Comp.1 | Comp.2 | Comp.3 | Comp.4 |
|---|---|---|---|---|
| Importance of Components | ||||
| Standard deviation | 1.53 | 0.87 | 0.85 | 0.43 |
| Proportion of Variance | 0.58 | 0.19 | 0.18 | 0.05 |
| Loadings | ||||
| Similarities (verbal comprehension) | 0.45 | 0.57 | 0.60 | 0.33 |
| Digit span (short-term memory) | 0.40 | −0.76 | 0.49 | −0.13 |
| Symbol search (processing speed) | 0.58 | 0.26 | −0.29 | −0.72 |
| Coding (processing speed) | 0.54 | −0.19 | −0.57 | 0.60 |